Analysis of Historical data suggests that all those who entered market 6 months before elections have been able to get a rewarding returns post elections.
As per present trend going is good for Narendra Modi and he is likely to be Prime Minister once again though he may not be able to wrest same number of seats as done in 2014. Listen to what a Foreign Professor has to say about Narendra Modi here.
Bloomberg has already done an analysis on the subject and same is as depicted in the below chart. Do have a look and decide accordingly.